Testing method and apparatus



R. M GER I lTz sTTNG METHOD AND APPARATUS Filed Dec. 20, 1957 lllllmmmINVENTOR /CHHKP. M. ERL /Z llwllllllllllllllllllullllllllll.llllllllllll irme/Vey Sept. 22, 1959 R. M. GERLlTz 2,905,892

` TESTING METHOD AND APPARATUS Filed Dec. 20, 1957 4 Sheets-Sheet 2 Q NiNI/ENTOR. Q maf/HRD M. @mL/TZ Sept. 22, 1959 R, M. GERLITZ 2,905,892

TESTING METHOD AND APPARATUS Filed Dec. 20, 1957 4 Sheets-Sheet 3 QV I l1' I n- Ik t Q t Q l w.

F D 96V' Sept. 22,l 1959 R M GERM-rz 2,905,892

TESTING METHOD AND APPARATUS United States Patent G MTH AND TUS RiclmdM.v Gerlitz, Blue 'ell,- Pa., assignorfn Philco Corporation,Philadelphia, Pa., a corporation of Penn- Sylvania A'pplicationDecember20,l 1957 Serial No". 704,027 41o claims. (el. S24-73)' This' inventionrelatesto the testinglof circuit subassemblies" suchf as: the`rso-called" printed: circuit panels Whichnare used in televisionreceivers and thelike.

Whilesev'eral types of'testing techniquesarenowlavailable, which allowthe testing'ofp'anels and/ or components' thereofas to a variety ofcharacteristic'sl'and functions, itr w'a'sthus'fa'r either impossible orundulyhv expensive to carry out a complete and satisfactory testingprogram as rapidly as is required in modern-electronicY fabrication,where millions" of each` type ofl circuit panelsV and the` like are'usually involvedl This-'applied particularly where thermionic tubes wereinvolved'. `It is therefore a' primary object hereof to'providesimpleand inexpensive testingZ procedures and means, capable of completeand satisfactory performance at' an extremelyr rapid' rate.'the'r'objectsfwill appear from the description of prefe'r'redLembodiments, which follows".VA

In a typical structure" embodying the invention the upper orcomponentsideof acircuit'panel tol be tested, a'nd whichv may comprisetube sockets and avariety of other 'components and connectors, ismechanically plugged i`"to"theA underside of a testing stand or jigwhich comprises the'tubes and similar non-permanent panelcomp'oilents.Vv ProvisiondsV madetoavoid delays in, as well as*incompleteness of, alll tube testing and related functions;` andfor'this purpose 'specialV arran'gementsjjof circiiitry/andassociatedparts'ma'y beused, as will? appear in'V greater detail' hereinafterlFigure 1 is a perspective-view'of'app'aratus'embodying the presentinvention.l`

Figure z'ls an enlarged pnrsnenfiv4 frente' View" of" al' portionvofsaidapp'aratu's.

Figure 3lis across"sectionalviev'vof 'a detail, taken`V along lineitl-2ly in Figre;

Figure-ris aL vien/similar toeFgi-fraf-bnf taken" along line 414,#

Figure 5 is another? vieu/"similari to'tFigl'lreS "show-ningafmodication"thereof: and

Figure -6 isv a diagram' of'electricaland other connections'l-us'ed in"ythe` machineL according" toFigi-el,

Referring initiallyn fol Figure if; the pnner 10" in be: tested,` withwire wrappinglugsll and other? components 12,-?? 13, etc. inserted:thereon, islmolinted on pins 1'4 upstanding from a supporting plate:Thisplate is" slidablefor'lI vertical traclmeniberstl; WhicharmountedonlatsttianaryfbaseX17 and whichY may'n'etadditionnlly' iiailniea sept.22, 1959 lCe sertedtherein, at 12B, which is to be u sedori-l thepalel10 when that panel is in actual" use, as distingishedfrorf the testingoperation performed in accordance herewith.

Electrical connections to a power supply, to'grouiid and tointerconnectedpanels are mad'efi-om the stand' 18, through a cable 19,'to achassis unit 20'suppor`t`ed on'the' base 17. Thisvchassis unitcontains" areceivcrtub'e 21, ofthe type to be employed in' actualluse,the" screen 22' vof which is visible behind a transparent front wall23'.` cabinet may also contain a conventional loud-speake 24 andthe'usl'lal tuning', switchingand control'meaiisZS.'

The panel-supporting plate"15"is` rigidly secured tothe ripper end of arod 26, connected witha pistn 27 in" a cylinder schematically shownfat28, said cylinder being mounted onl theundersidel'of the' base' 1 7b'yist'rctilll means 29 andV having threeiway valve`s"30', 31 connectedrespectively to the* top and'bottoin thereof, each of' sd valveshavingapressuresupply duct 32' and a VenterA waste'diict 332 Solenoids34 control' the valves idla'r'l'dy 3 1 to raise or low'eli` the'piston27, thereby raising'o lowering the'pa'riel' 10i For' this purposeelectrical connections 35'le'ad to th`e"solenoids`from a relay unit 36,which' mayV form a part of cabinet V20 extending below base'- 17. Pushbuttons 37, 38' may heused tocon'trol relay unit 36, desirably so thttheoperatormust operate both pushVv buttons to raise panel l-therebyprotecting the operatoragainst' accidental injury-while successiveoperationof one'p'ush button 38 may lowertlle" piston" and panel.In'addition'; a switch 39: may beprovidedas a limit switch and circuitholdiilgrmeans", as `will be described hereinafter.

As shown in Figure 2,' thelug` connectors 1'1 are desirably held inblock members 40,V whe'refror they pro` ject downwardly. Each block`40`may' bea plastic 'Hiern-V ber' having slidingt with a metallicconnectorwrd 1p1-A; and each blockv may vbe rigidly secured tothe'uiider'side" of a support plate 41, forming'part of jig 18. For suchsecurement screw members 42 may extend into the underside of the blockand through spacers 43 into plate 41. Each connectorrod 11A` has propervertical alignmentv with a lug 11 andproper lateral alignment withothe'rrods and contactors 11B, 12A, etc., foi" the'other members to be madepart of the test circuit. The'tube socketr contact'orsl 12A', etc., andlugf cont-actors 11A, etc., may be installed on diilEerent'levels,"`depending o'n the exact types of lugs 11, sockets'lZ and othercomponentsto be tested. All connect ors' 111fi`,4 12A', etel, as shown, arearranged in vertically dependingrelatior'l' to thejig sup'-y po'rt'plate41. By this v'expedient contactcan be made tothe panels tobe tested, insbstantiallythe same way asp Contact is made by'various terminals,incident to the insertion of the tubesand thejinstallation of theconnecting wires, as'used'in'an actual and Vcomplete receiifersetorequivalentinstrument.

Somelof thetube sockets 12X on panel 10 are providedt withshields 12Y;and in order to insure correct tube operation on' jig 18', thecorrespondirlgtube connectors" arefprovided with similar shieldslZZ.Different lengths'v of connector bodies 12A are exposed on the undersideo'f-platey 41, depending on the presence or absence ol' specific formof'members such as the shields `12Y.

The upper'portionl of -aconn'ector body 12A may corni` prise a standardtube-socket 12D, This andother details ofa tube socket connector areshown' in Figure 3l It will be seenI thattheconnector'body'12A'hasaseriesfo-fj terminal engaging pins 44 vertically slidable'therein and'downwardly extending therefrom, each having a spring' 45 biasing itdownwardly. The spring is used also to connect the pin 44 with one ofthe terminal members 46 n'the socket 12D forming part of connector12A.

Similarly"'the'slidable lug connectors 11A ligule'll,A

-mybbiasedwdownwardly by springsy 47. Each lug connector may have aconcave recess 48 at the bottom end thereof, in order to facilitate thecentering and establishment of proper contact with the top of lug 11 tobe contacted. The top end of the lug connector 11A may have a guide andstop member 49 secured thereto and slidably extending through the uppersurface of the plug 40.

While Figure 3 shows the tube connector 12A without a tube actuallyinserted in the socket unit 12D thereof, it will be understood that inthe actual operation of the testing device all required tubes, 12B,etc., are installed on the jig 18 as shown in Figure l. It is alsopossible and sometimes desirable to secure such tubes to the jig supportplate 41 in modified ways, for instance as shown in Figure 5, Here atube 12E is press-iitted into the inside of a sleeve 12F the outside ofwhich is press-fitted into a suitable aperture of the jig plate 41 sothat the lead terminals 44A of the tube itself can be contacted with thesocket terminals 12C on the panel 10. If the socket 12 requires no tubeshield, as shown in Figure 5, the holding sleeve 12F may be made ofnon-conductive material. In certain instances the construction of Figure5 is preferred over that of Figure 3 not only because of its greatersimplicity but also because of the absence of special capacitive and/orinductive elements, such as members 44, 4S. Various furthermodifications can of course be applied to such elements, as` willreadily be seen by persons skilled in this art.

Referring now to the electrical circuits of the testing device,illustrated in Figure 6: a power supply unit 50 is connected byconductor 51 and branch wire S2 with one of the lug connectors 11A onthe jig 18, this connector being vertically aligned with the powersupply Iug 11 of the panel 10 to be tested. On the underside of thispanel a copper strip, diagrammatically shown at 53, connects the lug 11with a branch 54 leading to the load system 55 for the tube to beplugged into the socket 12. A tube 12B, of the type required at thispoint, is plugged into terminals 56 of a corresponding socket 12D on thejig 18. The connection of load system 5S to tube 12B comprises a copperstrip conductor 57 with a branch 58 leading to the plate terminal 59 oftube 12B, through socket 12, 12D. Similarly the ground connection 60 ofthe load system 55 is connected with the cathode of tube 12B byconductor 61. The grid of tube 12B may be connected for instance byconductors 62, 63 with a lug 11M on panel 10 which by a lug connector11B on jig 18 may be connected, for instance, to one of the terminals oftelevision chassis 20.

The power supply lug 11 is shown as additionally connected with loadsystem 64 of a second tube socket 65 by conductor 66. The cathode of thesecond tube 67 for socket 65 is connected by a wire 68 to the groundconnection 69 of load system 64. Other tubes and components on panel maybe interconnected in similar ways; and terminals of components not shownand installed on panel 10 may for instance be connected with lugs.11N,110, ete. by conductors 70, 71, etc. In addition, the ground connection60 may be connected by a copper strip 72 to a lug 11F. Actual groundconnection and actual connections to other parts of the televisioncircuit are made through lug connectors 11B, 11C, 11D and 11E on thetest jig 18, which are vertically lined up respectively with the panellugs 11M, 11N, 110 and 11F, and which are connected with variousterminals on the tube 22 or chassis 20 or the circuits thereof.

lt will be seen that, when the piston 27 has raised the panel 10 so thatthe conductive panel lugs etc. are conductively coupled to theirrespectivecontactors on the test jig, the panel 10 and the jig 18jointly form, in substance, the equivalent of the panel, and of theconnections thereof, which have been omitted from the chassisv 20. Acomplete receiver circuit is thus provided by the raising of the piston27. It is however preferred to make 4 somewhat special provision forsome of the circuit elements or sub-combinations, as will now beexplained.

In the first place it is preferred to connect the filament heaters ofall tubes 12B, 67, etc. independently through a filament power supplysystem 73 which in its entirety is disposed on the jig 18 and whichincludes no circuitry forming part of panel 10. By this expedient thenecessity of heating up the cathodes is avoided, whenever contactbetween panel 10 and jig 18 is broken and then reestablished. This inturn greatly accelerates the testing procedure.

Because of the use of this independent filament supply system 73, thelilament connector lugs 11Q, 11R of the panel 10 and the printed stripsor circuit elements 74, 75, connected therewith remain unused andunconnected in the system as so far described. It is however preferredto test the panel circuitry in its entirety, including the strips 74,'75 and lugs 11Q, 11R. This becomes possible by making specialconnection to at least one set of panel socket terminals, connected withthe printed filament conductors 74, 75. For this purpose two conductors76, 77 are so installed on test jig 18 as to contact :filament terminalsin a panel socket 12, While not contacting iilament terminals in anysocket 12D forming part of jig 18. These special conductors 76, 77 mayalso be noted in Figure 2.

As shown in Figure 6 these special conductors are connected with a neonbulb 78, which serves to indicate the presence of satisfactory iilamentwiring on panel 10. It will be understood that substantially no timedelay is involved in the lighting up of a suitable neon bulb 78, uponthe establishment of contact at the exposed ends of 76, '77, whereas theheating up of the cathode filaments would involve some appreciabledelay. As further shown in Figures 2 and 6 additional Wires 79, 80 mayconnect the system 74 to 77 With other circuitry, such as that providedby tube socket contactors 81, which need not be discussed in detail. Asfurther shown in Figure 6, the testing of the circuits 74 to 80 may beachieved for instance by connecting a resistor 82 to the power supplyline 51, ahead of one of the lug contactors 11G for testing of lamentcircuitry, so that a suitable current may flow through resistor 82, lugcontactor 11G, lug 11R, copper strip 75, wire 77, neon bulb 78, wire 76,copper stn'p 74, lug 11Q and lug contactor 11F coupled to the groundconnector 11E.

In the actual use of the present method or system it is generallynecessary to test large numbers of identical panels 10 by means of a jig18 having contactors 11A, 12A, etc. at locations fitting the terminalunits 11, 12, etc. of the panels. Circuitry other than that of thepanels to be tested is usually installed in the chassis Z0. The testingof a panel starts by manually or automatically placing the panel on theindexing pins 14 of the lower support plate 15, Figure 1. the two pushbuttons 37, 38, Figures 1 and 6, thereby causing suitable energizationof the valve solenoids 34 which in turn causes rapid rising of piston27, plate 15 and panel 10 and contacting of the various panel terminals11, 12, etc. with the corresponding contactors 11A, 12A, etc. on thejig.

The establishment of this contact may substantially coincide with theclosing of the switch 39 which estab-y lishes connection fromthe powersupply unit 50 to the wire 51 through a normally open switch element39A.

This switch may also close a self-holding circuit for re-` lay 36,through a normally open switch element 39B, so that the electricalenergization of solenoids 34, initiated by the operation of the pushbuttons, continues upon the release of said buttons.

In the process of contacting the lugs 11 with the contactors 11A, thetip of each lug 11, Figure 4 is automat# cally centered by slidingenegagement with the concave surface 48, so that it is unimportantwhether such a lug may be slightly bent or uncentered, as is oftenunavoid;l

The operator then presses' able as a result of the insertion processesusedand/or the further handling of the panels. Provision for similarselfcentering may of course be provided in the socket-con.- tactingdevices, as is well-known in the art. It willY also be seen that slightdifferences of elevation between different lugs l1, etc. are notdeleterious, the contacting being resilient and/or slidingly yielding byvirtue of the use of springs 45, 47 or the like. v

When the panel has been contacted withv the stand 18, the unit 20, 22,24 exhibits proper sound and picture. This of course assumes that theunit has previously been tuned to a suitable transmission channel andthat the transmitter is operating.` The coming on of suitable sound andof a well defined picture repeats itselfupon the testing of each newpanel which is free from defect, whereas any kind of defect of a panelon the testv stand is reflected by faulty picture or sound, or bycomplete failure of picture or sound. Desirably, the determination isinstantaneous, and to this end the various tubes have their cathodesheated throughout the testing procedure by the larnent supply system 73,and the required power is supplied throughout the active testing of thepanel 10, through the closed switch 39A. The testing is also complete,as to all printed circuits and similar copper strips and the like, aswell as with respect to the Various components on the panel, allcomponent terminals other than the filament terminals being connected inthe precise way in which they are used in normal operation and thefilament terminals being separately connected to the neon bulb indicator78 which can be observed instantly, together with the picture on thescreen 23.

The testing operation performed with the present machine may in someinstances be preceded or followed by further tests, for instance thoseconducted in accordance with the invention described and claimed in theapplication of Walter W. Ludman et al., Serial No. 591,- 740, led June15, 1956, entitled Testing Apparatus and assigned to the assignee of thepresent invention. The Ludman et al. test procedure differs from thepresent one in that it is more detailed but less complete in an overallor functional Sense. The Ludman et al. test procedure establishes thepresence or absence of specified defects and also the exact location ofeach defect, if any, but it will not show whether the panel tested iscompletely satisfactory in the sense of its ultimate, comprehensivefunction. Thus it has been found, upon a complete check of circuitpanels passed by the Ludman et al. procedure, that between two and threepercent of such panels are still rejected upon further testing accordingto the present invention. Many thousands of panels and millions ofcomponents are represented by these two or three percent of the grandtotal. The manufacturers success in fabricating receivers and the likecan therefore be enhanced greatly by the use of the present testingprocedure.

While the testing according to this invention may precede or follow orreplace the testing according to the Ludman et al. invention, it may insome cases be preferred to expose the panels rejected by the presentmachine, and only those, to the detailed test according to Ludman et al.Considerable testing time is saved in that event. In addition it thenbecomes unnecessary, as to the majority of the panels, to apply testingtools to the solder spots on the underside of the panel, as contemplatedin the Ludman et al. procedure. This last-mentioned feature is importantin those instances where disturbance of protective layers on so-calledprinted circuitry must be avoided with maximum care.

On the other hand, a more complete testing program may call for both thecomprehensive functional testing of panels according to the presentinvention and the individual, so-called static testing of panel-mountedcomponents according to Ludman et al. The static test can be conductedso as to show not only defects and the lo- 6 cation.` thereof, butAspecific, quantitive data; for instance as to impedance, .inductance,capacitance, transformer ratio, rectifier` performance and many othercharacteristics, as applicable4 tothe various components. Thus-it may bepreferred, in theinterestof full quality control, to ap.-- ply} thestatic test to each panel directly after insertion of components, andthen as a final measure b'efore' instal-' lation of the panel to applythe functional'test` toeaeh panel which has-passedtlie-l static test.

While only a single embodiment ofthe invention andf a few ways of usingit have been described,- it should be understood that the detailsthereofare not to beconstrued as limitative of theinv'ention except insofar as'it is consistent Vwith the scope ofthefollowing claims.v

I claim:

1. Apparatus for testing ltelevision circuit panelshaving terminals' forthermionic tubesV thereomsaid apparatus comprising: a panel holder forholding such panels; a tube holder, holding such tubes and theirterminals, each of said terminals being indexed to engage, and eachexcept the filament terminals being arranged to contact thecorresponding terminals on the panels; means for completing a circuitincluding said filament terminals to permanently energize the filamentsof the tubes; a manipulator for moving the holders, one relative to theother, to temporarily engage the terminals on one of the holders withthose on the other; and a television device, devoid of a panel of thetype to be tested but interconnected with the terminals on the tubeholder and thereby adapted to be provided `with such a panel.

2. Apparatus as described in claim l, and additionally comprising apower supply unit for said television device; and means, controlled bythe manipulator, for connecting said power supply unit to saidtelevision device when, and only when, the terminals on the tube holderare engaged with those on the panel.

3. Apparatus as described in claim l, wherein the manipulator compris: afluid operated member; solenoid valve means for controlling movement ofsaid member; manual switch means for making and breaking circuits forthe solenoids of said rvalve means; and automatic switch means,controlled by the manipulator, for holding such circuits.

4. Apparatus as described in claim l, wherein said terminals on the tubelholder comprise lead members rigid with the tubes, socket meansengaging the lead members and metallic terminals extending from thesockets toward the panels to be tested.

5. Apparatus as described in claim 4, for the testing of panels havingterminals for shielded thermionic tubes, said apparatus comprisingshield means surrounding the corresponding sockets and tubes on `thetube holder.

6. Apparatus as described in claim l, wherein said terminals on the tubeholder are integral with said tubes thereon.

7. In apparatus for testing electronic circuit panels with socket typemeans permanently installed thereon for nonpermanent installation ofcircuit components including heater means: a first support, adapted tohave such a panel held and registered thereon; a second support, havingsuch components thereon, contactor means of said components beingindexed with the socket type means of the sor-registered panel, exceptfor the contactors of said heater means; means for energizing suchheater means independently of the panel; and means for moving thesupports relative to one another to make and break contact between thesocket type means and the contactor means.

8. Apparatus as described in claim 7 additionally comprising circuitmeans on the second support, indexed with the contactors of said heatermeans and adapted to energize said heater means upon the making of saidcontact.

9. In apparatus for testing electronic circuit panels with componentssuch as wire wrap lugs and tube sockets permanently installed thereonand provided for non-per- 7 manent installation of replaceable elementssuch as tubes and the like: a panel support, adapted to have such apanel held yand'registered thereon; a test stand, supporting saidreplaceable elements and a complete set of terminals of said replaceableelements, the several terminals on the test stand being insulated fromone another and indexed with corresponding components on the panel; andmeans for moving the panel support relative to the test stand tosimultaneously make contacts between terminals on the test stand andcorresponding components on a panel and thereafter simultaneously tobreak such contacts; the test stand including thermionic tube means andterminals thereof, indexed with corresponding -tube socket means on apanel, the test stand also including means for permanently energizingthe heater filaments of such tube means.

10. Apparatus as described in claim 9, and wherein 8 l the test standadditionally includes means for feeding electrical energy to those tubesupport terminals which Contact the Wire Wrapping lugs connected withthe lament circuit conductors on the panels; and means connected withthe lament terminals of at least one of the sockets, upon said making ofcontact, for indicating continuity of said filament circuits on thepanels.

References Cited in the tile of this patent UNITED STATES PATENTS1,365,734 Shackleton Jan. 18, 1921 1,646,152 Kleber Oct. 18, 19271,875,624 Lowry Sept. 6, 1932 2,728,890 Zimmerman Dec. 27, 19552,795,664 Conrad June l1, 1957 ...Awa-n

